The present disclosure relates to nanostructured composite metal hydrides. In particular, the present disclosure provides methods for fabricating hydrogen storage materials such as metal hydrides having hydrogen absorption/desorption kinetics that are suitable for transportation applications.
Metal borohydrides have been considered for many years as a potential hydrogen storage material because of their high hydrogen volume and weight capacities. For example, Mg(BH4)2 possesses a very high volumetric density and sets the record (14.9 wt %) for the gravimetric capacity of a reversible metal hydride system. The change in enthalpy (ΔH) for hydrogen desorption for this material is approximately ˜40 kJ/mole H2, which is not far from the ideal value of ΔH of 27 kJ/mol H2. However, hydrogen sorption is kinetically limited, and the temperatures required for significant hydrogen desorption are around 300° C. Reaction pathways appear to have important consequences for both kinetics and reversibility. Thus, there remains a need for advanced solid materials having improved capacities and reaction kinetics for the storage of H2 in order to advance technologies utilizing H2 as a renewable fuel.